SET SESSION query_cache_type=0;
SELECT
    p.sku,
    p.product_name,
    p.product_description,
    ( MATCH (p.product_name) AGAINST ('+word1 +word2 +word3' IN BOOLEAN MODE) * 10 ) AS score1,
    ( MATCH (p.product_description) AGAINST ('+word1 +word2 +word3' IN BOOLEAN MODE) * 20 ) AS score2,
    ( MATCH (p.product_name,p.product_description) AGAINST ('word1,word2,word3') * 30 ) AS score3
FROM products AS p
WHERE
    (
        ( MATCH (p.product_name) AGAINST ('+word1 +word2 +word3' IN BOOLEAN MODE) * 10 ) > 0 OR
        ( MATCH (p.product_description) AGAINST ('+word1 +word2 +word3' IN BOOLEAN MODE) * 20 ) > 0 OR
        ( MATCH (p.product_name,p.product_description) AGAINST ('word1,word2,word3') * 30 )
    ) AND
    p.sku NOT LIKE '4%'
ORDER BY score1 DESC,score2 DESC,score3 DESC LIMIT 0,15